Fix for MPLY-8456
Fix for MPLY-8456

https://eegeo-team.atlassian.net/browse/MPLY-8456
Preventing the default on contextmenu events on leaflet overlays.
Stopping propagation on mousedown events when clicking on leaflet
markers or markers with custom icons.
Buddy: Blair

eegeo/eegeo.js,eegeo/eegeo.js